That Roche F12 looks nice, I didn’t know it was still available.
In the photo (fasttech) it looks like the head is a different color than the body:
https://www.fasttech.com/products/1654/10002855/1308901
A good trapezoidal thread (acme thread), like Hoop said, would be nice. But I think “square threads” is just easier to understand when communicating with chinese sellers / makers.
Maybe Simon could consider acme threads for a future Convoy light. Perhaps they could slightly reduce costs since they are suppose to be easier to machine?
The S2+ I have seems to have a metric trapezoidal thread, if not just a highly truncated triangular thread.
The triangular threads centuries ago were steel, not aluminum.
They were made from wood before that. Aluminum threads work fine greased up.
+1000000042
This is a technique my dad taught me when I was very young and it is definitely one of the most useful bits of information I’ve been given through out my entire life when working with any type of metal. I often work on laptops and other precision pieces where cross-threading can be very difficult to remedy. This bit of advice is so ingrained in my brain that I never thread a screw into metal without first reversing until I feel that “click”. Thank you for mentioning that. Brought a smile to my face and fond memories of my father. 
Stop defending weak triangular aluminum threads. If you like them , buy them, but don’t try to pretend they’re not junk.
Aside from that brilliant bit of advice to turn back until you feel the “click” and then proceed (thank you Hoop for mentioning that) I definitely feel that triangle threads in aluminum is not a good idea. Triangle threads are great in metal-in-wood and acceptable in hard steel applications but for the most part just a bad idea in aluminum. It seems to me that triangle threads are best used in an application where said threads are meant to be used once. With repeated use in metal-on-metal applications there is little room for error and lubrication is critical. Square or “square-ish” threads are much more forgiving in something that will require repeated use of the threads like battery replacement or anything needing to be accessed repeatedly via a threaded part.
No need to get defensive there. I don’t see any threat of a triangle thread revolution in the flashlight world heading our way. 
Yes, trapezoidal or square threads are preferable for flashlights, but triangle threads aren’t junk.
Agreed.
I’m not sure why wight said that the S8 has triangular threads. Mine have square cut threads. Pretty square anyway…much more so that my S2+ or S2.
Yes, that’s how I was taught in school so many years ago when cleaning my 0-1” mics.
Just catching up on this thread of threads and I'll chime in on the s8. I've built up several of the s series lights recently all except the s3 s4. The S8 has been the most impressive to me so far. The quality is top notch and they defiantly have the best square cut threads out of the ones I've done. This light is great with a"FOY" bezel. It's easily filed down and polished.
Every one I've built got the "FOY" treatment because the crenulations just kill it.
Oh and it's also pretty grippy imo.
One other thing about the s8 clip. I like it and the only things that would make it better would be to make it deeper carry and make it titanium.
The S2+ has triangular threads with a 1.25mm pitch that are truncated. The crest and the root are both wider as a result of the profile being truncated, but it is the triangular thread form, which is to say it has a 60 degree thread angle as opposed to a 29(acme) or 30(metric trapezoidal) thread angle.
Cant speak to the S8.
Thanks for all that info above on Square, Triangular, tapered, spiral and other thread considerations.
Sure is interesting. Learn something new each day here.
S8 threads look good.
Triangular threads are fine when they are thick and squared off at the top. They are junk when they are thin and still have their soft pointy top. If you don’t know how to thread them, they’re a disaster waiting to happen. They are not suitable for klutzes in the general public.
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Congrats to Simon for improving the S8 !
Cheers for this - nearly fifty years on this planet and never heard that before and it makes perfect sense - thanks.
Strange how uncommon some “common knowledge” can be.
I’ve been back-turning every single threaded fastener I touch, for so long I don’t remember “learning” it. It just “seems like the right thing to do”. I’m not really ‘obsessed’, but every time I work with someone who just starts turning, I try to teach them that trick.
PS: What is this “cross-threaded” y’all keep mentioning?